Nipunadi Hettiarachchi | University of Greenwich (original) (raw)

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Papers by Nipunadi Hettiarachchi

Research paper thumbnail of Effectiveness and durability of protection against future SARS-CoV-2 infection conferred by COVID-19 vaccination and previous infection; findings from the UK SIREN prospective cohort study of healthcare workers March 2020 to September 2021

ABSTRACTBackgroundUnderstanding the duration and effectiveness of infection and vaccine-acquired ... more ABSTRACTBackgroundUnderstanding the duration and effectiveness of infection and vaccine-acquired SARS-CoV-2 immunity is essential to inform pandemic policy interventions, including the timing of vaccine-boosters. We investigated this in our large prospective cohort of UK healthcare workers undergoing routine asymptomatic PCR testing.MethodsWe assessed vaccine effectiveness (VE) (up to 10-months after first dose) and infection-acquired immunity by comparing time to PCR-confirmed infection in vaccinated and unvaccinated individuals using a Cox regression-model, adjusted by prior SARS-CoV-2 infection status, vaccine-manufacturer/dosing-interval, demographics and workplace exposures.ResultsOf 35,768 participants, 27% (n=9,488) had a prior SARS-CoV-2 infection. Vaccine coverage was high: 97% had two-doses (79% BNT162b2 long-interval, 8% BNT162b2 short-interval, 8% ChAdOx1). There were 2,747 primary infections and 210 reinfections between 07/12/2020 and 21/09/2021. Adjusted VE (aVE) decre...

Research paper thumbnail of Inactivation analysis of SARS-CoV-2 by specimen transport media, nucleic acid extraction Running title: SARS-CoV-2 inactivation Downloaded from

Journal of Clinical Microbiology, 2020

The COVID-19 pandemic has necessitated a multi-faceted rapid response by the scientific community... more The COVID-19 pandemic has necessitated a multi-faceted rapid response by the scientific community, bringing researchers, health officials and industry together to address the ongoing public health emergency To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2 Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation Given the wide array of inactivation reagents that are being used in laboratories during this pandemic, it is vital that their effectiveness is thoroughly investigated Here, we evaluated a total of 23 commercial reagents designed for clinical sample transportation, nucleic acid extraction and virus inactivation for their ability to inactivate SARS-CoV-2, as well as seven other common chemicals including detergents and fixatives As part of this study, we have also tested ...

Research paper thumbnail of Virucidal Efficacy of Guanidine-Free Inactivants and Rapid Test Buffers Against SARS-CoV-2: Implications for Risk Assessment of Diagnostic Procedures

A pathogen inactivation step during collection or processing of clinical samples has the potentia... more A pathogen inactivation step during collection or processing of clinical samples has the potential to reduce infectious risks associated with diagnostic procedures. It is essential that these inactivation methods are demonstrated to be effective, particularly for non-traditional inactivation reagents or for commercial products where the chemical composition is undisclosed. This study assessed inactivation effectiveness of twenty-four next-generation (guanidine-free) nucleic acid extraction lysis buffers and twelve rapid antigen test buffers against SARS-CoV-2, the causative agent of COVID-19. These data have significant safety implications for SARS-CoV-2 diagnostic testing and support the design and evidence-based risk assessment of these procedures.

Research paper thumbnail of Analysis of Inactivation of SARS-CoV-2 by Specimen Transport Media, Nucleic Acid Extraction Reagents, Detergents, and Fixatives

Journal of Clinical Microbiology

The COVID-19 pandemic has necessitated a multifaceted rapid response by the scientific community,... more The COVID-19 pandemic has necessitated a multifaceted rapid response by the scientific community, bringing researchers, health officials, and industry together to address the ongoing public health emergency. To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2. Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation.

Research paper thumbnail of Inactivation analysis of SARS-CoV-2 by specimen transport media, nucleic acid extraction reagents, detergents and fixatives

The COVID-19 pandemic has necessitated a rapid multi-faceted response by the scientific community... more The COVID-19 pandemic has necessitated a rapid multi-faceted response by the scientific community, bringing researchers, health officials and industry together to address the ongoing public health emergency. To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2. Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation. Given the wide array of inactivation reagents that are being used in laboratories during this pandemic, it is vital that their effectiveness is thoroughly investigated. Here, we evaluated a total of 23 commercial reagents designed for clinical sample transportation, nucleic acid extraction and virus inactivation for their ability to inactivate SARS-CoV-2, as well as seven other common chemicals including detergents and fixatives. As part of this study, we have also te...

Research paper thumbnail of Effectiveness and durability of protection against future SARS-CoV-2 infection conferred by COVID-19 vaccination and previous infection; findings from the UK SIREN prospective cohort study of healthcare workers March 2020 to September 2021

ABSTRACTBackgroundUnderstanding the duration and effectiveness of infection and vaccine-acquired ... more ABSTRACTBackgroundUnderstanding the duration and effectiveness of infection and vaccine-acquired SARS-CoV-2 immunity is essential to inform pandemic policy interventions, including the timing of vaccine-boosters. We investigated this in our large prospective cohort of UK healthcare workers undergoing routine asymptomatic PCR testing.MethodsWe assessed vaccine effectiveness (VE) (up to 10-months after first dose) and infection-acquired immunity by comparing time to PCR-confirmed infection in vaccinated and unvaccinated individuals using a Cox regression-model, adjusted by prior SARS-CoV-2 infection status, vaccine-manufacturer/dosing-interval, demographics and workplace exposures.ResultsOf 35,768 participants, 27% (n=9,488) had a prior SARS-CoV-2 infection. Vaccine coverage was high: 97% had two-doses (79% BNT162b2 long-interval, 8% BNT162b2 short-interval, 8% ChAdOx1). There were 2,747 primary infections and 210 reinfections between 07/12/2020 and 21/09/2021. Adjusted VE (aVE) decre...

Research paper thumbnail of Inactivation analysis of SARS-CoV-2 by specimen transport media, nucleic acid extraction Running title: SARS-CoV-2 inactivation Downloaded from

Journal of Clinical Microbiology, 2020

The COVID-19 pandemic has necessitated a multi-faceted rapid response by the scientific community... more The COVID-19 pandemic has necessitated a multi-faceted rapid response by the scientific community, bringing researchers, health officials and industry together to address the ongoing public health emergency To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2 Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation Given the wide array of inactivation reagents that are being used in laboratories during this pandemic, it is vital that their effectiveness is thoroughly investigated Here, we evaluated a total of 23 commercial reagents designed for clinical sample transportation, nucleic acid extraction and virus inactivation for their ability to inactivate SARS-CoV-2, as well as seven other common chemicals including detergents and fixatives As part of this study, we have also tested ...

Research paper thumbnail of Virucidal Efficacy of Guanidine-Free Inactivants and Rapid Test Buffers Against SARS-CoV-2: Implications for Risk Assessment of Diagnostic Procedures

A pathogen inactivation step during collection or processing of clinical samples has the potentia... more A pathogen inactivation step during collection or processing of clinical samples has the potential to reduce infectious risks associated with diagnostic procedures. It is essential that these inactivation methods are demonstrated to be effective, particularly for non-traditional inactivation reagents or for commercial products where the chemical composition is undisclosed. This study assessed inactivation effectiveness of twenty-four next-generation (guanidine-free) nucleic acid extraction lysis buffers and twelve rapid antigen test buffers against SARS-CoV-2, the causative agent of COVID-19. These data have significant safety implications for SARS-CoV-2 diagnostic testing and support the design and evidence-based risk assessment of these procedures.

Research paper thumbnail of Analysis of Inactivation of SARS-CoV-2 by Specimen Transport Media, Nucleic Acid Extraction Reagents, Detergents, and Fixatives

Journal of Clinical Microbiology

The COVID-19 pandemic has necessitated a multifaceted rapid response by the scientific community,... more The COVID-19 pandemic has necessitated a multifaceted rapid response by the scientific community, bringing researchers, health officials, and industry together to address the ongoing public health emergency. To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2. Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation.

Research paper thumbnail of Inactivation analysis of SARS-CoV-2 by specimen transport media, nucleic acid extraction reagents, detergents and fixatives

The COVID-19 pandemic has necessitated a rapid multi-faceted response by the scientific community... more The COVID-19 pandemic has necessitated a rapid multi-faceted response by the scientific community, bringing researchers, health officials and industry together to address the ongoing public health emergency. To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2. Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation. Given the wide array of inactivation reagents that are being used in laboratories during this pandemic, it is vital that their effectiveness is thoroughly investigated. Here, we evaluated a total of 23 commercial reagents designed for clinical sample transportation, nucleic acid extraction and virus inactivation for their ability to inactivate SARS-CoV-2, as well as seven other common chemicals including detergents and fixatives. As part of this study, we have also te...